Assembly of an integrated circuit (IC) when manufacturing an electronic package involves attaching a die or chip to a substrate. One example of a bonding process is the thermal compression bonding (TCB) process, which may be used for flip-chip bonding. The TCB process is not a batch process, unlike a conventional oven reflow process. The bonding of a flip-chip die during a TCB process is performed one die at a time. The die from the silicon wafer is flipped and transferred to a bond-arm with bumps on the die facing down. The die carried by the bond-arm is then placed onto a bonding location of the substrate or onto another die. A small compressive force is applied onto the die to press it against the substrate or the other die to ensure good contact between the die and the substrate or between the respective dice.
Impurities on bonding materials are undesirable because impurities prevent good contact between the bonding materials and bonding surfaces, which may result in performance degradation of final products. There are many potential sources of impurities in a die bonding process. For example, impurities may originate from foreign materials covering the surface of the bonding materials, arise from oxidation of the bonding materials under high temperature during the TCB process, or result from by-products generated during the bonding process.
It would be beneficial to reduce the amount of impurities which may interfere with the bonding process to avoid performance degradation of assembled electronic packages.